/*
*公共样式
*/
body{
    padding: 0;
    margin: 0;
    color: #333;
}
a{text-decoration: none;}
.br{
    border: 1px solid;
}
ul{list-style: none;}
*{padding: 0;margin: 0;}

.bg{
    background-color: red;
}
.bg-blue{
    background-color: blue;
}